[markofcain]

In your example you seem to be using the word "feminine" as a noun which is entirely possible while it is mostly used as an adjective.

I would argue that the use of word "feminine" as a noun can be done so only by an ellipsis in the sentence. If you follow that, then what you are actually saying is:

Match the feminine [words] with their masculine [words].

With an understanding of the ellipsis your statement is correct. However, I believe that most folks would supply the singular noun "word" which would make your statement incorrect.

Wouldn't you just say:

Match each feminine word with its masculine counterpart.

or

Match the feminine words with their masculine counterparts.

By explicitly stating the noun you remove the subjective filter which might cause the reader to render your statement awkward at best or incorrect in the worse case.

But what do I know? I'm just a pest control technician who likes language.